Malicious PDF — malware analysis report

Static analysis result for SHA-256 c257e425297a8e1d…

MALICIOUS

PDF

77.7 KB Created: 2021-09-21 01:20:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 7503c2e6a7aaa09e8b27307d851e8adf SHA-1: e1eeda711d868ae64babfa5fc3801e0a4d58ac64 SHA-256: c257e425297a8e1ddf4e597ee3a261a0d9267d39e2a2165e105e665c66e93716
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or redirecting users. Several heuristics indicate the PDF acts as a link farm, directing users to compromised WordPress sites and other domains, likely for phishing or malware distribution. The ClamAV detection and ML classifier further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7086

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://coretry.ru/uplcv?utm_term=google+docs+offline+on+android PDF link annotation
    • https://thefertilizerequipment.com/d/files/18271795850.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/1larl033julc58hbk5ka6erigp/69784882306.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/161353747e491d---98307477961.pdfIn PDF document text
    • http://grandwatergatehotel.com/upfile_hotel/files/nigovefitaxorijutulida.pdfIn PDF document text
    • https://banktapeunadana.com/tapeunadana/bank2/admin/userfiles/file/19082522046.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/48672027667.pdfIn PDF document text
    • http://immodraft.nrw/images/architekten_agentur_images_/file/rarixosiditavifawujowem.pdfIn PDF document text
    • http://studiomistretta.com/userfiles/files/sadogagumogizinusaneso.pdfIn PDF document text
    • http://vinhomescaurao.info/app/webroot/img/files/11640657391.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/40aa9203201b8065853b2463b04c1bde/99135608166.pdfIn PDF document text
    • http://hstechno.com/userData/ebizro_board/file/veninofapevakovajukelizex.pdfIn PDF document text
    • https://anninhsieuthi.online/upload/files/motiwekul.pdfIn PDF document text
    • http://sarigol.kr/userData/ebizro_board/file/kebebolipixoxut.pdfIn PDF document text
    • https://yuktogel.com/contents/files/japifaxirawoj.pdfIn PDF document text
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/a9dec210a02544c1967c02973fa56035/9386363491.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161328b334bc49---10161116750.pdfIn PDF document text
    • https://anctools.com/ckfinder/userfiles/files/bevavoxigaki.pdfIn PDF document text
    • https://self-storage.sg/images/uploadedimages/file/direpupuvif.pdfIn PDF document text
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/71734a5af47930830d922c854d6a67a4/25287086723.pdfIn PDF document text
    • http://paradisetnl.com/FileData/ckfinder/files/20210908_08FEEAF3EEF5830C.pdfIn PDF document text
    • https://myhoorayhealth.com/wp-content/plugins/super-forms/uploads/php/files/3a50eb3ba7716bcd3b7256d710d26cd0/10228127409.pdfIn PDF document text
    • http://shahgrp.com/uploads/91894752085.pdfIn PDF document text
    • http://tsutae-f.com/js/upload/files/bomuj.pdfIn PDF document text
    • https://semineebrasov.ro/printuri-fi/files/21976284681.pdfIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d577.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD577 17508 bytes
SHA-256: ac58dcfeb82d9c4f657654d65a5fd2cf33b2cf4d4bd89164974b35280a8245fd
font_01_sfnt_off000102f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102F3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011b0a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B0A 10592 bytes
SHA-256: 7ddda6e0130bc8bc481cbfa739e55eb7f544a4580c60e578e679108df9244c88